Plastics pose pollution threat to Galway Bay prawns

A frayed and tangled fibre from Galway Bay’s North Sound under 40-50 times magnification.

Prawns in Galway Bay are at risk of extinction – because of increasing micro-pollution on the seabed of the Atlantic Ocean.

That’s according to researchers at NUI Galway who have just published a study quantifying the increase of micro pollution along the western Irish continental shelf, which is the seabed of the shallow area near the coast.

Microplastics (plastics smaller than 0.5 mm) that enter the ocean tend to be ingested by prawns which can have detrimental repercussions for this species including ‘reduced fitness and potential reproductive failure.’

Dr Audrey Morley, senior author of the study and a lecturer in Physical Geography at NUI Galway, has warned that these findings could spell trouble for the national fishing industry, particularly in Galway.

According to a report carried out by Atlas Marine Institute on commercial fisheries for shellfish around Ireland, sales of prawns were valued at €47.3m in 2015 – accounting for approximately half of the total value of shellfish during that time.

Loic Trahan, Managing Director of Breizon which is a seafood business located in Rossaveal, is well aware of the importance of prawns to the industry.

“Prawns are and have been a key product in the seafood industry in the west of Ireland and their potential extinction would be a major blow,” he said.

While not directly related to the microplastic pollutants in the sea, he said that regulations have been introduced to combat the possible extinction of certain shellfish.

“We see steps being taken to preserve the population such as measures against landing under-sized prawns which was the case in the past so that has helped.

“The pollution factor is another issue and we don’t know the full impact it has on prawn fisheries so more research has to be done in that respect,” he added.

Dr Audrey Morley was in agreement on that and believed that more research was needed to ‘understand the mechanisms influencing interactions of microplastics with individual species and ecosystems.’

Loic Trahan said he had noticed a drop in prawn landings – but that it was difficult to determine the exact cause.

“There has been a drop in the landings of prawns over the last number of years but there are many factors involved- whether it’s due to over fishing or more fishing vessels moving to the west, it remains to be seen,” he added.

The microplastics recovered by the researchers appeared to be secondary microplastics – remnants of the breakdown of larger plastic items.

The study, which was published in the international journal Scientific Reports, stated that the pollutants may be originating from plastic polymer fishing gear or land based contributions from nearby industry, water treatment plants, or households.

The researchers say that the understanding of this form of pollution ‘is crucial for gauging environmental risk’.